JPH10137861A - Drawing and ironing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of galling in the drawing and ironing of the manufacture of an aluminum DI can or the like and in particular to surely prevent the generation of galling even in not only an alloy other than 3004 alloy and a DC material bit also a CC material. SOLUTION: The die, whose base material is coated with a hard thin film of >=Hv 2500 and moreover whose surface roughness is <=Ra 0.05μm, is used as the die for the ironing pass of at least the final stage in ironing. Especially, a diamond-like carbon film (DLC film) is used as the hard thin film. Also, the thickness is specified to be within the range of 0.5-2.5μm. Further, the hardness of the die base material is specified to be >=HRc 58.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drawing and ironing method applied to the production of a can body (DI can body) of a two-piece aluminum can, and particularly to an aluminum obtained by applying continuous casting and rolling. The present invention relates to a drawing and ironing method suitable for performing drawing and ironing using a rolled alloy plate as a workpiece.

[0002]

2. Description of the Related Art Drawing (drawing) is performed on a thin metal plate.
ng) and then re-drawing (Redr) if necessary
awing) and then ironing (Ironin)
The so-called drawing and ironing process (DI process) for applying g) has been frequently used in the manufacture of can bodies of two-piece aluminum cans.

[0003] In drawing and ironing, generally, during ironing, the metal on the surface of the workpiece adheres to the ironing dies, and flaws or discolored patterns are formed on the surface of the workpiece in parallel with the ironing direction, that is, galling occurs. May occur. Such galling impairs the appearance quality of the product, and is a fatal defect particularly in applications where the aluminum base is exposed without coating the surface, such as an aluminum can. Further, when the galling is severe, the material breaks from the portion where the galling occurs during the ironing, so that the work must be interrupted and the work efficiency may be reduced. Further, when the material breaks due to the galling during the ironing process, the broken pieces may damage the ironing die and the processing device. Therefore, in drawing and ironing, it is strongly desired to suppress the occurrence of galling during ironing.

[0004] As a measure for preventing the occurrence of galling, a method of improving lubricity by applying a lubricating oil stock solution to the surface of a workpiece as a pretreatment for drawing and ironing has been conventionally known, and a method of lubricating oil during ironing. A method of selecting an appropriate lubricating oil that does not easily cause oil film breakage by combining various things, and a method of appropriately adjusting the surface roughness of the work material to improve the oil retaining property of the surface are applied. ing.

[0005] A typical example of a product to which the drawing and ironing method is applied is an aluminum DI can body. Generally, a material for an aluminum DI can body is Al-Mn-.
An Mg-based alloy 3004 alloy or 3104 alloy is used. The reason is that these alloys have relatively high strength, are excellent in formability, and have excellent mechanical properties such as low work hardening during ironing, but this is not only the case. In the alloy of (1), a conventional general rolled plate manufacturing process, that is, a process of casting by a DC casting method (semi-continuous casting method), then performing hot rolling and cold rolling and performing intermediate annealing as necessary (hereinafter referred to as “ When a rolled plate is manufactured by the “DC process”, it is also a major reason that galling hardly occurs in drawing and ironing. That is, D of this kind of alloy
There are many Al-Mn-Fe-based and Al-Mn-Fe-Si-based crystallized compounds in the rolled sheet by the C process, and these crystallized compounds exhibit solid lubricity, and It is known that a self-cleaning effect can be obtained by the above-mentioned method, and furthermore, a recess formed in the vicinity of the crystallized compound on the surface can function as a lubricating oil reservoir to improve oil retention, thereby suppressing galling.

[0006] As conventional dies for drawing and ironing, alloy tool steel, high-speed steel, cemented carbide and the like are generally used.

[0007]

As described above, Al-M
n-Mg 3004 alloy or 3104 alloy is D
It is not only excellent in strength and formability as a material for I can body, but also effective in preventing galling during ironing. It is said that it is difficult to continuously and stably produce a high-quality can body because galling easily occurs in ironing and is inferior in ironing workability. Therefore, 3004 alloy, 3104
Aluminum alloys other than alloys have not been applied to DI can bodies even though they have excellent strength and formability (formability other than ironability).

[0008] Recently, as a process for manufacturing an aluminum alloy plate for an aluminum DI can body, a continuous DC process has been used in place of a conventional general DC process for the purpose of energy saving, environmental preservation, equipment cost and reduction of manufacturing cost. A manufacturing process to which the casting rolling method is applied, that is, a process of performing cold rolling without performing hot rolling normally and performing intermediate annealing as necessary (hereinafter referred to as “CC process”) after continuous casting and rolling. It is desired to use. That is, in the case of the CC process, the hot rolling step which is indispensable in the DC process can be omitted. However, this hot rolling step requires a large amount of heat energy and electric energy. Large amount of CO
₂ occurs. Therefore, by applying a CC process that omits hot rolling, we aim to reduce energy costs, reduce equipment costs by eliminating the need for hot-rolling equipment, and also eliminate CO ₂ gas generation and protect the environment. You can do it.

However, in the case of a rolled plate manufactured by the DC process as described above, even if the alloy is a 3004 alloy or a 3104 alloy, which hardly causes galling in ironing, the CC
In the case of a rolled plate to which the process is applied, there is a problem that galling easily occurs in ironing. That is, in general, a rolled aluminum alloy plate manufactured by the CC process has a high strength and is excellent in formability other than ironability, but generally has a high solid solution amount of an alloy element and a small grain size of a crystallized material. The workability is poor and galling is likely to occur.
It has been hesitant to use a rolled plate to which the CC process has been applied for an aluminum DI can body even with the 04 alloy or the 3104 alloy.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a drawing and ironing method which basically suppresses the occurrence of galling during ironing. The present invention also suppresses the occurrence of galling during ironing with an aluminum alloy other than the 3004 alloy and 3104 alloy conventionally used in DI can bodies.
Aluminum D other than 104 alloy
It is also intended to be usable for I can bodies. Further, the present invention suppresses the occurrence of galling during ironing even when an aluminum alloy rolled plate obtained by applying the CC process is used, thereby making it possible to produce a rolled plate for an aluminum DI can body by the CC process. Can be applied to save energy in the rolled plate manufacturing process,
It also aims at environmental conservation and cost reduction.

[0011]

As a result of various experiments and studies conducted by the present inventors to solve the above-mentioned problems, at least the final die among the dies used for drawing and ironing, especially the dies for ironing. As a dice for the pass,
A hard thin film having a specific hardness (Hv 2500 or more) and a specific surface roughness (Ra 0.05 μm or less), particularly diamond-like carbon, is formed on the surface of a conventional die material made of a general die material such as cemented carbide. Membrane (DLC
It has been found that by forming a hard thin film typified by a film and performing drawing and ironing using such a die, it is possible to effectively suppress the occurrence of galling during ironing. It has been reached.

More specifically, the invention according to claim 1 is a drawing and ironing method in which drawing and ironing are performed on a metal base plate, wherein at least the final stage of the ironing pass in the ironing is performed using a die base. A hard thin film having a Vickers hardness of 2500 or more is coated on the surface of the material in contact with the metal base plate, and the hard thin film has a surface roughness Ra of 0.0
It is characterized in that a die having a diameter of 5 μm or less is used.

According to a second aspect of the present invention, there is provided the drawing and ironing method according to the first aspect, wherein a diamond-like carbon film is used as the hard thin film.

According to a third aspect of the present invention, there is provided the drawing and ironing method according to the first aspect, wherein the thickness of the diamond-like carbon film is 0.5 to 2.5.
It is within the range of μm.

The drawing and ironing method according to the fourth aspect of the present invention is the drawing and ironing method according to the first aspect.
As the die substrate, one having a Rockwell hardness of 58 or more and a surface roughness Ra of 0.05 μm or less is used.

According to a fifth aspect of the present invention, there is provided the drawing and ironing method according to the first aspect of the present invention, wherein the die has an intersection of a surface forming an inlet half angle and a surface forming an outlet half angle, or the inlet half angle. A die having a curved surface having a radius of curvature of 0.1 mm or more is used at the intersection between each surface forming the exit half angle and the bearing portion.

According to a sixth aspect of the present invention, there is provided the drawing and ironing method according to the first aspect of the present invention, wherein the metal plate is made of an aluminum alloy melt having a thickness of 50 mm at a cooling rate of 100 ° C./sec or more. Continuous casting and rolling to the following plates and further cold rolling to a final plate thickness of 0.35 to 0.2 mm
An aluminum alloy plate is used.

The drawing and ironing method of the invention according to claim 7 is the drawing and ironing method according to claim 1, wherein
0.5 to 2.0 wt% of Mg, Mn
0.5-1.8 wt%, Fe 0.1-0.7 wt%, S
i0.05-0.5wt%, Cu0.05-0.5wt
% And 0.005 to 0.20 wt% of Ti alone or in combination with 0.0001 to 0.05 wt% of B, and if necessary, 0.05 to 0.3 wt% of Cr.
%, One or more of Zn 0.1 to 0.5 wt%, and the balance consists of Al and inevitable impurities. After continuous casting and rolling, cold rolling is performed at a final cold rolling reduction of 40% or more. An aluminum alloy rolled sheet having a sheet thickness in the range of 0.35 to 0.2 mm and containing no intermetallic compound having a particle diameter exceeding 10 μm is used.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Generally, in drawing and ironing such as production of a DI can body, after drawing a metal plate, redrawing is performed as necessary, and then two or three steps. Usually, ironing is performed in the above-described ironing pass. However, in the draw ironing method of the present invention, a drawing die (including a redrawing die) and an ironing used in each ironing pass in the ironing are performed. Of the processing dies, at least a die base material surface (the surface in contact with the metal base plate) coated with a hard thin film is used as an ironing die used in an ironing pass at the final stage of ironing. Of course, it is most preferable to use a die coated with a hard thin film as a die for drawing and a die for all passes of ironing. However, galling is more likely to occur in ironing than drawing, and in each pass of ironing, However, since galling is likely to occur in the final pass with the highest working degree, the present invention uses at least an ironing die coated with a hard thin film as the ironing die in the final pass of ironing.

Here, the hardness of the hard thin film coated on the die substrate must be Hv 2500 or more. That is, when the present inventors repeated a number of experiments on the relationship between the material of the die and the occurrence of galling,
The surface hardness of the die is closely related to the occurrence of galling, and when the surface hardness is less than Hv 2500, in the case of an aluminum alloy rolled plate other than the 3004 alloy rolled plate obtained by the DC process, the cohesion of the workpiece to the die surface is reduced. It is easy to cause galling on the product surface as a result, and the surface hardness is set to Hv 2500 or more, so that galling can be reliably reduced even in an aluminum alloy rolled plate other than the 3004 alloy rolled plate by the DC process. It turned out to get. Therefore, in the present invention, the hardness of the hard thin film coated on the surface of the die substrate in contact with the workpiece is defined as Hv 2500 or more.

Examples of such a hard thin film having a hardness of Hv 2500 or more include SiC, TiC, HfC, ZrC, and WC.
And the like, nitrides such as BN, TiN, and Si ₃ N ₄ , diamond films, diamond-like carbon films (hereinafter referred to as DLC films), and films in which these are mixed. Among these, the DLC film is particularly optimal. That is, the DLC film is not only hard, but also has self-lubricating properties because it contains diamond, carbon, and polymer components, and has an extremely smooth surface because of its amorphous structure. Thus, remarkable smoothness is obtained. And like this, DLC
In addition to being hard with Hv 2500 or more, the film has a self-lubricating property and excellent surface smoothness, so that the coefficient of friction between the film and the material to be processed is low, and the film is excellent in abrasion resistance and simultaneously processed. The material is less likely to adhere to the die surface, and as a result, the occurrence of galling can be significantly reduced. In addition to DLC film, BN (boron nitride) also has a self-lubricating property, so that although it is slightly inferior to DLC, it can exhibit excellent galling resistance as compared with other hard thin film materials.

Methods for coating these hard thin films on a die substrate include ion plating and various CVD methods.
And PVD methods. In particular, as a method of forming a DLC film, there are sputtering of graphite, ion beam evaporation of carbon, plasma CVD of methane, and the like, and a plasma CVD method is generally used. Note that the hardness of the same film usually varies depending on the film forming method and the film forming conditions such as the processing temperature. Therefore, it is desirable to select the optimum film forming method and conditions.

The surface roughness of the hard thin film as described above, especially the surface in contact with the workpiece, must be adjusted to a center line average roughness Ra specified in JIS B 0601 of 0.05 μm or less. is there. Roughness of hard thin film is 0.05
If it exceeds μm, the work material is likely to adhere to the die surface during ironing, and as a result, galling tends to occur on the product surface. That is, if the die surface is rough and hard at the time of ironing, the surface of the work material is scraped off, and the shaved work material adheres to the die surface, so that galling easily occurs, and especially the surface hardness is increased. When Hv is 2500 or more, the surface roughness is Ra0.05.
If it exceeds μm, the tendency becomes remarkable. Therefore, the surface roughness Ra of the hard thin film coated on the die substrate is 0.1.
It is necessary to be not more than 05 μm.

In the case of a DLC film or an amorphous BN (αBN) film among the various hard thin films described above, the surface roughness Ra can be reduced to 0.05 μm or less as it is formed. In the case of other hard thin films, it is necessary to polish them with diamond powder or the like after film formation or to apply a means such as lapping in order to reduce the surface roughness Ra to 0.05 μm or less. Also, as described above, the DLC film or B
Since the N film itself has self-lubricating properties, the surface roughness R
Although the generation of galling can be suppressed reliably at 0.05 μm or less, in the case of another hard thin film having no self-lubricating property, the surface roughness Ra is set to 0. It is desirable that the thickness be not more than 02 μm.

The thickness of the hard thin film coated on the die substrate is suitably in the range of 0.5 to 5 μm. When the thickness of the hard thin film is less than 0.5 μm, it is easy to peel off from the base material when it is worn. On the other hand, coating thicker than 5 μm is not only uneconomical but also makes the film brittle and peels off. Easier to do. Therefore, in order to provide a sufficient service life, a film thickness in the range of 0.5 to 5 μm is desirable. In the case of a DLC film, in particular, 0.5 to 2.5 μm
The range of m is appropriate.

Further, as the die substrate on which the hard thin film is coated, it is desirable to use a material having a Rockwell hardness (HRc) of 58 or more. If the hardness of the base material is less than HRc58, it is too soft, so even if a hard thin film is coated on it, the hard thin film cannot exhibit excellent performance such as low friction and abrasion resistance. Due to the high surface pressure, the amount of elastic deformation of the die substrate itself increases, and the deformation of the hard thin film also increases, so that the hard thin film is easily cracked or peeled. Therefore, it is desired to select a material having an HRc of 58 or more as the die base material, and a material having an HRc of 61 or more is more preferable. Specific examples of the die base material include alloy tool steel, high-speed steel, and cemented carbide, and among them, cemented carbide is particularly preferred.

In order to reduce the surface roughness of the hard thin film coated on the die substrate to Ra 0.05 μm or less as described above, the surface roughness of the die substrate before coating the hard thin film is reduced by polishing or polishing. It is desirable to adjust Ra to 0.05 μm or less by lapping or the like. In other words, the surface roughness after forming a hard thin film is affected by the roughness of the substrate surface before film formation. Roughness also increases, and it takes much labor and time to adjust the surface roughness to Ra 0.05 μm or less thereafter, and it may be difficult to produce a hard thin film with a uniform thickness. Therefore, these problems can be prevented by setting the surface roughness of the die substrate before forming the hard thin film to Ra 0.05 μm or less.

An intermediate layer may be provided between the die substrate and the hard thin film in order to improve the adhesion of the hard thin film. As the intermediate layer, depending on the material of the die base material and the hard thin film, a material having good adhesion to both may be appropriately selected. For example, aluminum, silicon, a metal such as tungsten, or an alloy thereof, or a material thereof. Metal carbide, nitride, oxide, or the like can be used. Although the thickness of such an intermediate layer is not particularly limited, it is usually sufficient to set it to about 100 nm to 1 μm. If the thickness of the intermediate layer is less than 100 nm, the effect of improving the adhesiveness of the hard thin film cannot be obtained, while if it exceeds 1 μm, the adhesiveness will not be further improved and the economics will only be impaired.

Further, as a die used in the drawing and ironing method of the present invention, in the case of a die having no bearing portion between the entrance half-angle and the exit half-angle, the dice between the surface forming the entrance half-angle and the surface forming the exit half-angle are used. Intersection is radius of curvature 0.1m
m or more, it is desirable to use a shape having a smooth curved surface. On the other hand, in the case of a die having a bearing portion substantially parallel to the center axis of the die between the entrance half angle and the exit half angle, the entrance The intersection of the half-angle surface, the half-angle exit surface, and the bearing is 0.1 mm in radius of curvature, respectively.
It is desirable to use a shape having such a smooth curved surface.

This point will be described with reference to FIGS. 1 to 4. FIG. 3 shows a general example of a conventional ironing die 1 having a bearing portion 3, and in this case, the inlet half angle θ ₁ is determined. Intersection 6 between the approach part 4 to be formed and the bearing part 3
The intersection 7 between the bearing portion 3 and the release portion 5 forming the exit half angle θ ₂ is usually a sharp edge as shown in FIG. Conventionally, it is considered that it is important to make the shape of the intersections 6 and 7 as sharp edges in order to obtain good surface roughness and good surface quality of the processed product. It has been thought that loss of the metal leads to the occurrence of shortage of cans or the occurrence of poor appearance such as black streaks or vertical scratches.
However, in the case of using a die coated with a hard thin film as in the case of the present invention, if the shape of these intersections is a sharp edge, conversely, if the shape of the intersection is a sharp edge due to impact or abrasion during processing, etc. It has been found that this results in an undesirable result that the thin film is easily peeled off. Although FIGS. 3 and 4 show the dies having the bearing portions 3, the dies having no bearing portions 3 also include the approach portion 4 forming the inlet half angle θ ₁ and the release portion 5 forming the outlet half angle θ ₂ . It has been found that a similar problem occurs when the intersection is defined as a sharp edge. According to experiments by the present inventors, as shown in FIG. 1, the intersection P ₁ between the approach portion 4 forming the entrance half angle θ ₁ and the release portion 5 forming the exit half angle θ ₂ when no bearing portion is provided, or As shown in FIG. 2, when the bearing portion 3 is provided, an intersection P ₂ between the approach portion 4 forming the entrance half angle θ ₁ and the bearing portion 3 and an intersection P between the release portion 5 forming the exit half angle θ ₂ and the bearing portion 3. ₃ can be prevented by setting each of them as a smoothly curved surface having a radius of curvature of 0.1 mm or more. It has been found that if the surface roughness is adjusted as described above, the occurrence of shortage of cans and poor appearance of products can be suppressed. Therefore, when applying the method of the present invention,
It is desirable that the shape of these intersections be a smooth curved surface having a radius of curvature of 0.1 mm or more.

As the rolled aluminum alloy plate to be subjected to the drawing method of the present invention, a plate manufactured by a continuous casting and rolling method (CC process) is preferable. In other words, as described above, by applying the CC process and omitting the hot rolling step, it is possible to reduce energy costs and equipment costs, and furthermore, to achieve environmental conservation by reducing the generation of CO ₂ gas. However, in the conventional general drawing and ironing method, there is a problem that when a plate made by the CC process is used, galling easily occurs. On the other hand, by using a die coated with a hard thin film to have a surface hardness of Hv 2500 or more and a surface roughness Ra of 0.05 μm or less, it is possible to prevent the occurrence of galling even in a plate obtained by the CC process. Because
Therefore, the effect of the method of the present invention is most effective in the case of a plate obtained by the CC process.

Here, it is appropriate that the cooling rate in the continuous casting and rolling is 100 ° C./sec or more. If the cooling rate is less than 100 ° C./sec, the casting rate will be low and productivity will be impaired. The thickness of the continuous cast rolled plate is suitably 50 mm or less. If the sheet thickness during continuous casting and rolling exceeds 50 mm, it will be difficult to obtain a sufficient cooling rate of 100 ° C./sec or more, and the load on the subsequent cold rolling will also increase.

The continuous cast rolled sheet may be subjected to cold rolling to obtain a final thickness. However, during the cold rolling or between the continuous casting rolling and the cold rolling, the cold rollability may be reduced. Intermediate annealing may be performed as necessary in order to improve. The conditions of the intermediate annealing are not particularly limited, but, for example, a method in which a batch furnace is used to hold at a temperature of 320 ° C. or more for 2 hours or more, or a temperature of 45 ° C. is obtained by applying continuous annealing.
What is necessary is just to apply the method of performing rapid cooling at 0 degreeC or more. Final rolling rate in cold rolling (When intermediate annealing is not performed in the middle of cold rolling, it means the rolling rate from the thickness of the continuous cast rolled sheet to the final thickness, and intermediate annealing is performed in the middle of cold rolling. In the case of sandwiching, the rolling reduction after the intermediate annealing to the final sheet thickness) is preferably 40% or more. That is,
If the final rolling reduction is less than 40%, it is difficult to sufficiently secure the strength of the final rolled sheet, and the final rolling reduction of 40% or more makes it possible to secure the necessary strength as a DI can or the like. The final thickness by cold rolling is 0.35 to
A range of 0.2 mm is appropriate. Final thickness is 0.35
If it exceeds mm, it will be difficult to achieve a sufficient weight reduction as a DI can or the like, while if it is less than 0.2 mm, the abrasion resistance required for the container may not be secured.

Further, the component composition of the aluminum alloy to which the drawing and ironing method of the present invention is applied is not particularly limited, but examples of the Al-Mn-Mg alloy include, for example, Mg 0.5 to 2.0. 0 wt%, Mn 0.5-
1.8 wt%, Fe 0.1 to 0.7 wt%, Si 0.0
5 to 0.5 wt%, Cu 0.05 to 0.5 wt%, and Ti 0.005 to 0.20 wt% alone or in combination with B 0.0001 to 0.05 wt%, with the balance being Al and An alloy consisting of unavoidable impurities can be suitably used. Such Al-Mn-M
The component composition of the g-based alloy is determined in order to ensure sufficient strength, moldability, abrasion resistance, and recyclability for a DI can body or the like, but alloys having other component compositions, such as 5
As for the 182 alloy, it is a matter of course that a DI can body or the like can be obtained without applying galling by applying the method of the present invention.

Further, as the rolled aluminum alloy plate to be subjected to the drawing and ironing method of the present invention, a rolled plate having no intermetallic compound having a particle size of more than 10 μm (crystal or precipitate) does not exist. preferable. That is,
If large intermetallic compound particles exceeding 10 μm are present, the vicinity of the particles is likely to be a starting point of breakage during molding, and for example, the end face is likely to be peeled off in flange processing (opening of the opening of the can opening). .

In the drawing and ironing method of the present invention, the method of lubrication in drawing and ironing is not particularly limited, and a water-soluble emulsion type coolant similar to the conventional one may be used. However, in the case of the present invention, since the coefficient of friction during processing is reduced and the adhesion resistance of the die is improved, the concentration of the emulsion can be reduced, and a solution type coolant can be used instead of the emulsion. In this case, it is possible to reduce the burden of cleaning work after manufacturing and the like, and to reduce the cost.

[0037]

【Example】

Example 1 For each of the aluminum alloys A to C shown in Table 1, a plate having a thickness of 0.30 mm was formed by a DC process or a CC process.

Here, as a DC process, an ingot having a thickness of 500 mm is obtained by a semi-continuous casting method (DC casting method), and hot-rolled into a 3.5-mm hot-rolled sheet according to a conventional method, and further subjected to primary cooling. After performing cold rolling to a sheet thickness of 0.75 mm, an intermediate annealing was performed at a heating rate of 20 ° C./min.
The temperature was raised to 0 ° C., and continuous annealing was applied at a cooling rate of 20 ° C./min, followed by cold rolling to 0.30 mm as final cold rolling. On the other hand, as the CC process, cooling rate 1
Continuous casting and rolling was performed at a cooling rate of 00 ° C./sec or more to obtain a continuous cast rolled plate having a thickness of 6 mm, and further cold-rolled to 0.75 mm as primary cold rolling, and then subjected to the same conditions as above for intermediate annealing. , And cold-rolled to a thickness of 0.30 mm as final cold-rolling.

With respect to these aluminum alloy sheets, DI processing was performed using various dies, and an experiment was conducted to continuously produce 1000 cans of 350 ml-sized aluminum can bodies at a rate of 250 cans / min. Here, as the die, a cemented carbide is used as a base material, and the die base material is not coated with a hard thin film, and the hard thin film is coated with any of DLC, TiC, TiN, CrN, and BN. A die was used. In the case of using a coating die, the coating die was used for all of the drawing die, the redrawing die, and the three-stage ironing die. As the lubricating oil, a water-soluble emulsion type coolant was used, and its concentration was set to 2%, which was thinner than the conventional general concentration of 4%.

Table 2 shows the results of can making when using the rolled aluminum alloy sheet obtained by the DC process. The hardness (Hv) and surface roughness (Ra) of the die surface were examined, and the results are also shown in Table 2.

[0041]

[Table 1]

[0042]

[Table 2]

In Table 2, no. Reference numeral 1 is a comparative example using a cemented carbide die not coated with a hard thin film for a DC process material of alloy A equivalent to 3004 (current material). In this case, a 3004 alloy DC process material is used. Even if the hardness of the die was less than Hv 2500, no galling occurred and good DI processability was exhibited. No.
3 is an alloy B with a slightly higher Mg content than the 3004 alloy
This is a comparative example using a cemented carbide die not coated with a hard thin film for the DC process material of Example 1. Also in this case, no galling occurred and good DI workability was exhibited. While N
o. No. 5 is a comparative example using a cemented carbide die having no hard thin film coated on a DC process material of alloy C corresponding to 5182. In this case, galling occurred.

On the other hand, No. 2, No. 4, no. 6, N
o. 7, no. Reference numeral 10 denotes a hard metal substrate coated with a hard thin film and having a surface hardness of Hv 2500 or more and a surface roughness Ra of 0.0
In the examples of the present invention using a die having a diameter of 5 μm or less, no galling occurred in any case, and good DI processability was exhibited. Among these, in particular, No. 6, no. 7,
No. 10 is an example of alloy C equivalent to 5182, which was conventionally considered to easily cause galling. In these cases, however, no galling occurred.
It can be seen that 82 alloy can also be used as a material for DI cans.

On the other hand, no. 8, No. 9 is 518
For alloy C equivalent to two alloys, the hardness of the hard thin film surface is H
In the comparative examples using dice less than v2500, weak galling occurred in these cases.

Further, Table 3 shows the results of can making when using the rolled aluminum alloy plate obtained by the CC process. The hardness (Hv) and surface roughness (Ra) of the die surface were examined, and the results are also shown in Table 3.

[0047]

[Table 3]

In Table 3, no. 11 is a comparative example using a cemented carbide die not coated with a hard thin film for a CC process material of alloy A equivalent to 3004. In this case, since the die surface hardness is less than Hv 2500, it is strong during molding. The breaking of the can was caused by the galling, and the molding had to be interrupted. No. No. 21 is a comparative example in which a cemented carbide die having no hard thin film was used for a CC process material of alloy B having a slightly higher Mg content than the 3004 alloy. Same as 11.

On the other hand, no. 12, No. 13, No. 1
5, no. 20, no. 22 is an example of the present invention using a die in which various hard thin films are coated on a die base made of a cemented carbide and the surface hardness is Hv 2500 or more and the surface roughness Ra is 0.05 μm or less. In these cases, no galling occurred, good DI workability was exhibited, and no adhesion of aluminum to the dies was observed at all.

On the other hand, no. 18, No. 19 is a comparative example using a die coated with a hard thin film but having a surface hardness not satisfying the condition of Hv 2500 or more. In this case, galling occurred and adhesion of aluminum to the die was recognized. No. 14, No. 16,
No. Reference numeral 17 denotes a surface coated with a hard thin film but having a surface roughness R
a is a comparative example using a dice that did not satisfy the condition of 0.05 μm or less, in which case also galling occurred,
Adhesion of aluminum to the dies was also observed.

Example 2: No. 1 of Example 1. 1, No. 1
1, No. Using the can body obtained in No. 12, flange formability was evaluated. As an evaluation method, evaluation was performed by performing a hole expansion test of the flange portion after necking by a conventional method. That is, after DI processing, trimming and washing are performed, and further, 200 ° C. × 20
After a four-stage necking process, a hole expansion test was performed, and the hole expansion diameter until breakage occurred in the hole expansion test was measured. Table 4 shows the results. At the same time, 10 μm in the rolled aluminum alloy plate in each example was used.
Since the existence of intermetallic compound particles exceeding m was examined, the results are also shown in Table 4.

[0052]

[Table 4]

No. 1 is DC of alloy A equivalent to 3004
This is a comparative example using a cemented carbide die which is not coated with a hard thin film for the current material, that is, the current material. 12 is DLC of Hv 2500 or more for CC material of the same alloy A
This is an example of the present invention using a die covered with a film, and as described above, no galling occurred in any case. However, as shown in Table 4, in the latter case, 10 μm
It was found that no intermetallic compound exceeding the above was present, and the flange formability was superior to the former. No. 11 is a comparative example using a die not coated with a hard thin film for the CC process material of the same alloy A. In this case, not only galling occurs, but also cracks occur at the time of hole expansion starting from the galling scratches. Thus, it was found that the flange formability was poor.

Embodiment 3: No. 1 in Embodiment 1. Under the same conditions as in No. 12, a continuous can was produced in the same manner as described above, using a die in which the material of the base material was changed. Table 5 shows the results together with the hardness of the die substrate.

[0055]

[Table 5]

In Table 5, no. 12, No. 23,
No. 24 indicates that the hardness of the die base material used is HR.
c58 or more, and in these cases, peeling of the thin film of the die did not occur, and good moldability was exhibited. On the other hand, no. 2
5, no. Reference numeral 26 is an example in which the hardness of the die base material did not satisfy the condition of HRc 58 or more. In this case, thin film peeling occurred on a part of the die, and galling occurred on that part.

Example 4: No. 1 in Example 1. Under the same conditions as in Example 12, the same continuous can was produced by changing the shape of the die in various ways. That is, for each of the dice having the bearing portion and the dice having no bearing portion, the intersection shape between the surface forming the entrance half angle and the surface forming the exit half angle or the entrance half shape, the intersection shape between the surface forming the exit half angle and the bearing portion is described. Continuous cans were made by changing to a smooth shape having a radius of curvature of 0.3 to 1.0 mm or a sharp edge shape. Table 6 shows the results.

[0058]

[Table 6]

In Table 6, No. 12, No. 28,
No. Reference numeral 29 denotes an example using a dice having an intersection shape having a smooth curved surface with a radius of curvature of 0.1 mm or more, and in each of these cases, a hard thin film does not peel off, and good galling does not occur. DI workability was shown. On the other hand, no.
27, no. Numeral 30 is an example using a dice having a sharp intersection point as a sharp edge. In these cases, peeling occurred in a part of the hard thin film, and galling occurred in that part.

[0060]

According to the method of the present invention, among the dies used for drawing and ironing, at least Hv 2500 is used as the ironing die for the ironing process in the final pass of ironing.
The above hard thin film is coated and the surface roughness Ra is 0.05
The use of a layer having a diameter of not more than μm can reliably prevent the occurrence of galling, and particularly,
3004 alloy DC material or 3 which is often used as I can body material
Aluminum alloy plate other than 104 alloy DC material, for example, 5
Drawing and ironing can also be performed on a 182 alloy DC material or a 3004 alloy continuous cast and rolled material (CC material) without causing galling. As described above, according to the method of the present invention, it is possible to draw and iron a material which has been conventionally unsuitable for drawing and ironing, and therefore, it is possible to use a material having a higher strength than in the prior art.
Since it is possible to further increase the strength and reduce the thickness of the drawn and ironed product such as a can body, it is possible to use a continuous cast rolled material for the production of the drawn and ironed product, By applying continuous casting and rolling instead of the DC process at the time of plate manufacturing, energy saving, environmental conservation, reduction of manufacturing cost, and the like can be achieved. Further, according to the method of the present invention, since the limit ironing rate that can be formed by one ironing is improved, three ironing operations have conventionally been performed for manufacturing an aluminum DI can. By applying the method described above, stable can-making can be performed even by two ironing operations, and the DI processing cost and the equipment cost can be reduced.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional view showing a main part of an example of a die used in the present invention.

FIG. 2 is an enlarged sectional view showing a main part of another example of a die used in the present invention.

FIG. 3 is a cross-sectional view showing a conventional general die as a whole.

FIG. 4 is an enlarged cross-sectional view showing a main part of the conventional die shown in FIG.

[Explanation of symbols]

3 bearing part theta ₁ inlet half angle theta ₂ exit half angle P _1, P _2, P ₃ intersections

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI B21D 37/01 B21D 37/01 51/26 51/26 X B22D 11/00 B22D 11/00 E C22C 21/06 C22C 21/06

Claims (7)

[Claims] Claims: 1. A drawing and ironing method in which drawing and ironing are performed on a metal base plate, and at least a surface of a die base material that is in contact with the metal base plate as a die of an ironing path at the last stage in the ironing process. Using a die coated with a hard thin film having a Vickers hardness of 2500 or more and having a surface roughness Ra of 0.05 μm or less. 2. The drawing and ironing method according to claim 1, wherein a diamond-like carbon film is used as the hard thin film. 3. The drawing and ironing method according to claim 1, wherein the thickness of the diamond-like carbon film is in the range of 0.5 to 2.5 μm. 4. The drawing and ironing method according to claim 1, wherein the die base material has a Rockwell hardness of 58 or more and a surface roughness Ra of 0.05 μm or less. 5. An intersection of a surface forming an entrance half angle and a surface forming an exit half angle, or an intersection of each surface forming an entrance half angle and an exit half angle, and a bearing having a curvature radius of 0.
Using a die formed with a curved surface of 1 mm or more,
The drawing and ironing method according to claim 1. 6. A continuous casting and rolling of the molten aluminum alloy into a plate having a thickness of 50 mm or less at a cooling rate of 100 ° C./sec or more as the metal base plate, followed by cold rolling to a final thickness of 0.35 to 0.2 mm. 2. The drawing and ironing method according to claim 1, wherein an aluminum alloy plate is used. 7. The method according to claim 7, wherein the metal element plate is Mg 0.5 to 2.0.
0 wt%, Mn 0.5-1.8 wt%, Fe0.1-
0.7 wt%, Si 0.05-0.5 wt%, Cu0.
0.05 to 0.5 wt% and 0.005 to 0.5% Ti.
20 wt% alone or B 0.0001-0.05
wt% in combination with Cr0.
0.5 to 0.3 wt% and Zn 0.1 to 0.5 wt%, with the balance being Al and unavoidable impurities. After continuous casting and rolling, the final cold rolling reduction is 40% or more. 2. The drawing and ironing method according to claim 1, wherein an aluminum alloy rolled sheet which is subjected to cold rolling to a sheet thickness in the range of 0.35 to 0.2 mm and contains no intermetallic compound having a particle diameter exceeding 10 μm is used.